Polyolefin compositions with improved mechanical and barrier properties

Abstract

Polymer compositions may include a polymer matrix containing a polyolefin, one or more polymer particles dispersed in the polymer matrix, wherein the one or more polymer particles include a polar polymer selectively crosslinked with a crosslinking agent, and wherein the one or more polymer particles has an average particle size of up to 200 μm. Processes of preparing a polymer composition may include mixing a polyolefin, a polar polymer, and a crosslinking agent; and selectively crosslinking the polar polymer with the crosslinking agent in the presence of the polyolefin. Methods may include increasing stress cracking resistance of a polyolefin by mixing a polar polymer with the polyolefin; and selectively crosslinking the polar polymer in the presence of the polyolefin with a crosslinking agent to form crosslinked polar polymer particles dispersed in the polyolefin.

The invention claimed is: 
     
       1. A polymer composition comprising:
 a polymer matrix comprising a polyolefin; and 
 one or more polymer particles dispersed in the polymer matrix, wherein the one or more polymer particles comprise a polar polymer selectively crosslinked with a crosslinking agent, and wherein the one or more polymer particles has an average particle size of up to 200 μm; 
 wherein the polymer matrix further comprises a functionalized polyolefin present in the range of 0.1 wt % to 15 wt %, based in the total mass of the polymer composition, and 
 wherein the polar polymer comprises at least one functional group selected from the group consisting of hydroxyl, carboxylic acid, carboxylate, ester, ether, acetate, amide, amine, imide, imine, sulfone, phosphone and their derivatives. 
 
     
     
       2. The polymer composition of  claim 1 , wherein the one or more polymer particles has an average particle size of up to 50 μm. 
     
     
       3. The polymer composition of  claim 1 , wherein the polyolefin is present in a range of 99.5 wt % and 30 wt %. 
     
     
       4. The polymer composition of  claim 1 , wherein the polyolefin is present in a range of 99.9 wt % and 90 wt %. 
     
     
       5. The polymer composition of  claim 1 , wherein the polyolefin comprises one or more polymers selected from a group consisting of ethylene homopolymers, copolymers of ethylene and one or more C3-C20 alpha-olefins, propylene homopolymers, copolymers of propylene and one or more comonomers selected from ethylene or C4-C20 alpha-olefins, heterophasic propylene polymers, olefin terpolymers, and blends thereof. 
     
     
       6. The polymer composition of  claim 1 , wherein the polar polymer is selected from the group consisting of polyvinyl alcohol, ethylene vinyl alcohol copolymer, ethylene vinyl acetate copolymer and mixtures thereof. 
     
     
       7. The polymer composition of  claim 1 , wherein the crosslinking agent is selected from the group consisting of maleic anhydride, maleic acid, itaconic acid, itaconic anhydride, succinic acid, succinic anhydride, succinic aldehyde, adipic acid, adipic anhydride, phthalic anhydride, phthalic acid, glutaraldehyde, their derivatives and mixtures thereof. 
     
     
       8. The polymer composition of  claim 1 , wherein the functionalized polyolefin is a polyolefin functionalized with one or more selected from a group consisting of maleic anhydride, maleic acid, acrylic acid, methacrylic acid, itaconic acid, itaconic anhydride, methacrylate, acrylate, epoxy, silane, succinic acid, succinic anhydride, ionomers, and their derivatives. 
     
     
       9. The polymer composition of  claim 1 , wherein the polymer composition presents a Normalized Property Balance Index (N PBI ) within the range of 1.5 to 10, wherein the N PBI  is calculated according to the formula: 
       
         
           
             
               
                 
                   N 
                   PBI 
                 
                 = 
                 
                   
                     PBI 
                     sample 
                   
                   
                     PBI 
                     reference 
                   
                 
               
               , 
             
           
         
       
       where PBI sample  is the property balance index for a sample of the polymer composition, and PBI Reference  is the property balance index of a reference polymer composition consisting of the polyolefin; and wherein PBI is calculated according to the formula: 
       
         
           
             
               
                 PBI 
                 = 
                 
                   
                     FM 
                     × 
                     IR 
                     × 
                     ESCR 
                   
                   
                     10 
                     7 
                   
                 
               
               , 
             
           
         
       
       where FM is the stiffness of the sample as determined by secant modulus of elasticity at 1% deformation according to ASTM D-790 in units of MPa, IR is the IZOD impact resistance according to ASTM D-256 in units of J/m, and ESCR is the environmental stress cracking resistance according to ASTM D-1693 in units of h. 
     
     
       10. The polymer composition of  claim 1 , wherein the polymer composition presents up to 60% increase in barrier to oxygen when compared to a reference polyolefin according to ASTM-1927. 
     
     
       11. The polymer composition of  claim 1 , wherein the polymer composition presents up to 60% increase in barrier to volatile organic compounds (VOC) when compared to a reference polyolefin. 
     
     
       12. A manufactured article comprising the polymer composition of  claim 1 . 
     
     
       13. A polymer composition comprising:
 a polymer matrix comprising a polyolefin; 
 one or more polymer particles dispersed in the polymer matrix, the one or more polymer particles comprising a polar polymer reacted with a crosslinking agent to form a crosslinked polar polymer, wherein the crosslinking agent reacts selectively with one or more functional groups present on the polar polymer, and wherein the polar polymer is crosslinked in the presence of the polymer matrix, and 
 wherein the crosslinking agent is selected from the group consisting of maleic anhydride, maleic acid, itaconic acid, itaconic anhydride, succinic acid, succinic anhydride, succinic aldehyde, adipic acid, adipic anhydride, phthalic anhydride, pthalic acid, glutaraldehyde, their derivatives and mixtures thereof. 
 
     
     
       14. A polymer composition comprising:
 a polymer matrix comprising a polyolefin; and 
 one or more polymer particles dispersed in the polymer matrix, wherein the one or more polymer particles comprise a polar polymer selectively crosslinked with a crosslinking agent, and wherein the one or more polymer particles has an average particle size of up to 200 μm, 
 wherein the polymer matrix further comprises a functionalized polyolefin present in the range of 0.1 wt % to 15 wt %, based in the total mass of the polymer composition, and 
 wherein the polar polymer is selected from the group consisting of polyvinyl alcohol, ethylene vinyl alcohol copolymer, ethylene vinyl acetate copolymer and mixtures thereof.